Field of the Invention
The present invention relates to an image forming apparatus and a system.
Description of the Related Art
A technique in which in an image forming apparatus that uses an electrophotographic method, variable control of a developing condition, a transfer condition, a conveyance condition, or a fixing condition in accordance with a type of recording material, is performed using a sensor for determining a recording material, has been proposed. There are apparatuses that provide, as a specific configuration for a sensor for determining the recording material, a light source at a position opposite a sensor for determining a print paper, and by detecting transmitted light, the thickness of the print paper is determined according to the transmitted light. Also, a method in which the surface of a recording material is captured by a CCD sensor or a CMOS sensor, and a roughness of the recording material is detected from a magnitude relation of the density thereof, and a method in which the thickness of a recording material is detected from the length of a shadow that appears at an end portion of a recording material have been proposed.
In an image forming apparatus in which a sensor for determining a recording material is mounted, as described above, productivity decreases in the case where the above described determination method is performed in relation to all recording materials. Accordingly, a method of controlling so as to confirm the result of detecting the paper type of a feeding unit in which recording materials are contained according to the result of determination of a number of sheets specified in advance, and thereafter omitting recording material determination processing has been proposed (Japanese Patent Laid-Open No. 2007-055814).
However, in the foregoing conventional image forming apparatus, because the processing to determine the recording material of the number of sheets specified in advance is necessary, there is a problem in that a productivity will necessarily decrease proportionally to that specified number of sheets.